(1) Field of the Invention
The present invention relates to organoclay compositions and methods of making them and for using them for removing impurities from contaminated liquids, and more particularly to organoclay compositions formed by contacting a microporous non-swelling aluminosilicate substrate with an alkylamine base.
(2) Description of the Related Art
Contaminated liquids are commonly produced as a result of industrial activities, transportation over land and water and storage and handling. Accidental releases, runoff, and the like are common problems that result in oil contaminated water, which is caused by spilling, leaking, or otherwise contacting the water with crude or refined oils, lubricants, fuels, or exhaust. The contaminants can render the liquid hazardous or unsuitable in terms of potability, industrial exposure, appearance, odor, growth of microorganisms, or environmental release. Methods of treating contaminated liquids are known, including the use of certain clays, treated clays, activated carbon and other materials as absorbents or adsorbents for the contaminants. Some of these materials have a high capacity for removing oils, for example, but may also absorb large amounts of water, or lose their structural integrity. Absorption of an excess amount of water can impair or limit the capacity of the material in removing the target impurities.
The modification and/or use of various types of clays as absorbents for contaminants has generated wide interest. General information on various clays and other aluminosilicates can be found, for example, in The Industrial Minerals Handybook II, Peter W. Harben, Ed., pp. 9-11 (attapulgite and sepiolite), pp. 21-25 (bentonite), and pp. 200-202 (zeolites), Industrial Minerals Division, Metal Bulletin PLC, London (1995).
In U.S. Pat. No. 2,367,384, Tymstra et al. described the use of a broad range of hydrophobic organic materials as coatings for a variety of fine particulate solids in order to obtain compositions capable of absorbing oil from water. Hauser, in U.S. Pat. No. 2,531,427, described the production of a swelling clay product that has been treated with an organic xe2x80x9coniumxe2x80x9d compound to form a material that formed a swollen gel upon contact with organic liquids.
Jordan, in U.S. Pat. No. 2,966,506, described the formation of modified clay complexes by reacting a swelling bentonitic clay, which had been ion exchanged, with an organic ammonium salt. The complexes were said to be useful for gelling an organic liquid.
U.S. Pat. No. 2,971,922 taught organophilic mineral compositions consisting of 25-70 parts of a clay and 30-75 parts of a fatty acid amide. These colloidal clay materials were used as gelling agents, foundry binders, and rheology modifiers.
U.S. Pat. No. 3,024,164 described monoethanolamine (MEA) coated clay compositions for use as a pesticide carrier.
U.S. Pat. No. 3,080,214 disclosed the treatment of attapulgite to make a filter aid by forming a dispersion, grinding, and drying the material.
U.S. Pat. No. 3,298,849 disclosed hydrating, swelling clays modified with alkanolamine acid salts.
In U.S. Pat. No. 3,487,928, Canevari taught the use of a montmorillionite clay that had been treated with an organic cationic agent, such as an amine or a glycol, for the removal of dispersed droplets of oil from water.
U.S. Pat. No. 3,617,561 disclosed the use of attapulgite with anionic polyacrylamide as a clarifying agent.
U.S. Pat. No. 3,901,818 disclosed a complex for binding hydrocarbons, comprising a solid hydroxyl-containing substrate, activated with an acid halide, then covalently bound with primary amines.
U.S. Pat. No. 4,054,515 disclosed the absorption of heavy metals from water using attapulgite or sepiolite.
U.S. Pat. No. 4,079,001 disclosed the purification of industrial effluents with an adsorptive material made from a cellulosic carrier treated with a clay-polyamidopolyamine complex.
U.S. Pat. Nos. 4,116,825 through 4,116,828 disclosed the use of attapulgite and sepiolite to adsorb hormones (""825), toxins (""826), viral microorganisms (""827), and pesticides (""828) from water.
U.S. Pat. No. 4,167,481 disclosed a process for metals removal using cation exchangers (tectosilicate and phyllosilicate clays) in the presence of polyamines.
U.S. Pat. No. 4,386,010 disclosed compositions of attapulgite treated with quaternary ammonium or phosphonium surfactants.
U.S. Pat. No. 4,444,665 disclosed a method of purifying aqueous liquids with calcined attapulgite treated with quaternary cationic surfactants.
Beall, In U.S. Pat. No. 4,473,477, described a method for absorbing organic wastes onto an organoclay formed by reacting a quaternary ammonium salt and a smectite-type clay. In U.S. Pat. No. 4,517,094, the same inventor described a two-stage method for removing organic contaminants from aqueous liquids, where the first step of the method involved passing the waste through a column packed with an organoclay.
U.S. Pat. No. 4,769,078 disclosed organophilic clays made by reacting smectic clays with quaternary ammonium compounds and a betaine.
U.S. Pat. Nos. Re. 34,041 and 4,781,860 disclosed a method of disposal of radioactive or hazardous liquid wastes, by adding attapulgite or sepiolite clay and stirring until the mixture solidified.
U.S. Pat. No. 4,802,985 disclosed a water treatment material of organic thermoplastic polymer, inorganic particulate material, and organic cationic crosslinked polymer.
U.S. Pat. No. 5,028,388 taught an immobilizing process for metallic and organic pollutants, by absorbing them on a layered clay mineral modified with a quaternary ammonium compound.
U.S. Pat. No. 5,057,467 described the use of polyalkylenepolyamine and an optional latex to improve the filtration rate and viscosity of clay slurries.
U.S. Pat. No. 5,071,587 disclosed a composition for removing turbidity, metals, and organics from drinking water, comprising clay, coagulant or flocculent, biocide, and activated charcoal.
U.S. Pat. No. 5,231,063 taught a composite adsorbent for odors, comprising salts of aromatic amino acids, an acid, and a transition metal.
U.S. Pat. No. 5,238,575 described a method of absorbing hydrocarbons, using acid leached bentonite modified with an alkyl ammonium salt that is protonated with an organic aliphatic acid. Optional co-additives were also listed.
U.S. Pat. No. 5,320,773 disclosed a method of making a dry solid water purification composition, by impregnating a mineral with a biocide and a coagulant or flocculant.
U.S. Pat. No. 5,407,879 taught a method of absorbing contaminated liquids with smectite clays impregnated with a water soluble polymer.
U.S. Pat. No. 5,454,955 disclosed a method of clarifying deinking waste with hectorite clay, cationic coagulant, and anionic flocculant.
U.S. Pat. No. 5,554,288 described the use of filter papers impregnated with additives to remove halogen, organic, and metal cation wastes.
U.S. Pat. No. 5,556,547 disclosed the use of polymer modified smectite clays to thicken or solidify sludges.
U.S. Pat. No. 5,667,694 disclosed a method of heavy metals removal using an organoclay formed from a smectite clay and a quaternary ammonium salt.
U.S. Pat. No. 5,670,435 disclosed a composition of bentonite with acid for treating waste water.
U.S. Pat. No. 6,080,319 taught a method of removing inorganic ionic contaminants from water using a mineral modified with an organic ionic compound and an amphoteric surfactant.
Despite the advances that have been made in the area of organoclay compositions for treating liquid wastes, there remains a need for economical, effective compositions that can be used in different types of treatment settings. Specifically, for inline treatment settings, a non-swelling composition would be preferable for cartridge containment. It would also be useful if such compositions provided low resistance to liquid flow, and were capable of maintaining structural integrity while demonstrating low water absorption and a high capacity for organics. There is also a need for new methods of purification of contaminated liquids using such solid sorbents.
Briefly, therefore, the present invention is directed to a novel composition for purifying contaminated liquids, the composition comprising a granular microporous non-swelling aluminosilicate substrate having absorbed thereon a primary, secondary or tertiary alkylamine base.
The present invention is also directed to a novel method of purifying contaminated liquids comprising contacting the contaminated liquid with the composition described above.
The present invention is also directed to a novel method of making a composition for purifying contaminated liquids, the method comprising contacting a granular microporous non-swelling aluminosilicate substrate with a primary, secondary or tertiary alkylamine base so that the alkylamine base is absorbed into the pores of the aluminosilicate substrate.
The present invention is also directed to a novel method of purifying a contaminated liquid comprising contacting the contaminated liquid with an effective amount of a composition comprising a granular microporous non-swelling aluminosilicate substrate having a primary, secondary or tertiary alkylamine base absorbed thereon.
The present invention is also directed to a novel method for removing organic impurities from water comprising contacting the water with an effective amount of a composition that is produced by contacting a granular microporous non-swelling aluminosilicate substrate with a primary, secondary or tertiary alkylamine base so that the alkylamine base is absorbed into the pores of the aluminosilicate substrate.
Among the several advantages found to be achieved by the present invention, therefore, may be noted the provision of an economical, effective organoclay composition for treating liquid wastes that can be used in different types of treatment settings, the provision of a non-swelling composition suitable for cartridge containment, the provision of a composition that provided low resistance to liquid flow, and is capable of maintaining structural integrity while demonstrating low water absorption and a high capacity for organics, and the provision of new methods of purification of contaminated liquids using such solid sorbent composition.
In accordance with the present invention, it has been discovered that a novel and effective composition for purifying contaminated liquids can be formed by combining a granular microporous non-swelling aluminosilicate substrate with a primary, secondary or tertiary alkylamine base. The subject composition also can be generally referred to herein as an xe2x80x9corganoclayxe2x80x9d. The novel organoclay compositions can be formed by contacting attapulgite or sepiolite with an alkylamine base, and these organoclay compositions have been found to be useful in purifying contaminated liquids.
In general terms, the present organoclays are formed by contacting certain types of aluminosilicate substrate materials (such as certain clays) with an alkylamine base. The main components of the novel composition can exist as a blend by nature of physical entrapment, adsorption, absorption, coating, and the like, or alternatively could be bonded by covalent, ionic, hydrogen bonding, hydrophobic association chelation, or other means. The subject organoclay compositions are more hydrophobic than their unmodified starting minerals by nature of the incorporation of the alkylamine base modifier. The organoclay compositions of the invention are also generally characterized by a higher capacity for absorbing hydrocarbons in the presence of water, as compared with the unmodified clay minerals.
The quaternary amine modified clays of the prior art are generally less hydrophobic than the organoclay compositions of this invention and as a result they have a inferior capacity for absorbing hydrocarbons in the presence of water. This reduced capacity for absorbing hydrocarbons could be a result of water absorption into the quaternary amine modified clays. A further disadvantage of the quaternary amine modified clays is the reduced mechanical strength of the particles relative to the granular particles of the present compositions. Higher mechanical strength of the particles is desirable in applications such as purification of contaminated water streams, where the water has a tendency to soften and swell clay particles and cause breakage and clogging of equipment.
The subject organoclay compositions also can be made without the use of an acid halide as has been practiced in the prior art. The acid halide materials are hazardous and represent additional processing steps to achieve covalent binding of the modifier to the clay. Surprisingly, we have found that the present organoclays do not require activating reagents or covalent binding of the alkylamine base to the aluminosilicate mineral substrate.
The aluminosilicate substrate that is used to make the subject compositions are microporous aluminosilicate minerals selected from the group consisting of attapulgite, sepiolite, palygorskite, Fuller""s earth, zeolite, and hormite. As used herein, the alumninosilicate substrate alternatively may be referred to as a xe2x80x9cclayxe2x80x9d. An idealized formula representing attapulgite is (OH2)4(OH)2Mg5Si8O20-4H2O and sepiolite is represented by Si12Mg9O30(OH)6(OH2)4-6H2O, but natural variations occur in the mineral deposits. Attapulgite and sepiolite are clays of the hormite group, and palygorskite and Fuller""s earth are synonyms for attapulgite. Based on this, any member of the hormite, attapulgite, Fuller""s earth, sepiolite, or palygorskite mineral classifications that meets the criteria for the aluminosilicate substrate that are described herein can be used as the aluminosilicate substrate of the invention.
In another embodiment, a zeolite can be used as the aluminosilicate substrate of the invention. Zeolites are well known, from either synthetic or natural origin, and are characterized as crystalline microporous hydrated aluminosilicates having pores in the size range of 3-10 angstroms.
Attapulgite and sepiolite have a porous nature due to the needle-shaped crystal structure (which can also be described as xe2x80x9cchain typexe2x80x9d crystal structure). When an aluminosilicate substrate material of the present invention is described as being xe2x80x9cmicroporousxe2x80x9d, it is meant that the material has a Brunauer, Emmett, Teller (BET) surface area of at least about 100 m2/g and an average pore size of under about 10 angstroms. It is preferred that the substrate has a BET surface area of about 150-300 m2/g. The pores in the preferred attapulgite and sepiolite minerals have an average size of about 6 angstroms.
The inventors have found that it is preferred that the aluminosilicate substrate be microporous. This porosity provides an effective surface area greater than that of an equivalent particle size distribution of non-porous material, such as sand, glass dust, and the like. The combination of microporosity with a particle having a granular size has been found to be particularly advantageous.
The microporous aluminosilicates of the present invention are characterized by a void volume of 10% to 70%, and preferably from about 30% to about 50%. The void volume can be defined as the volume percent capacity of the dried substrate to absorb a liquid without significant swelling. For example, a quantity of LVM attapulgite was found to absorb 50% of its volume in water without swelling more than 10%. When it is said that the present aluminosilicate substrates are non-swelling, it is meant that they exhibit swelling upon absorption of less than 20% by volume. It is preferred that the aluminosilicates swell less than 10% by volume.
The density of the porous aluminoslicate substrate is also an indicator of the extent of porosity. If completely non-porous, the density of a dried aluminosilicate would be in excess of 2,500 kg/m3. The dried aluminosilicates having a bulk density of 320 to about 2,400 kg/m3 are characterized as porous. It is preferred that the bulk density of the dried aluminosilicate substrates is from about 320 to about 1,000 kg/m3.
While the properties of the aluminosilicate that are described above are preferred to make the organoclay composition of the invention, it should be understood that the aluminosilicate might become somewhat less porous and more dense upon modification with the alkylamine base of the invention, and that the void volume would be decreased accordingly. The presence of moisture or solvents in the aluminosilicate would also have a similar effect.
When the aluminosilicate substrates are in hydrated form, the pores are filled with water molecules or hydrated cations that may be driven off by heating to 500xc2x0 C. to produce a low volatile material (LVM) clay. Clays dried at 200xc2x0 C. are referred to as regular volatile material (RVM) clays. While the organoclay compositions of the current invention may be prepared from hydrated, dried, calcined, LVM, or RVM clays, the preferred form is an RVM clay, and LVM clay is even more preferred.
Clays that are suitable for use in the present invention are preferably derived from a naturally occurring mineral source, but synthetic clays are expected to be effective as well. The clay is preferably provided in the form of a granular solid having a high surface area, but a finely divided clay, an agglomerated clay, or even a slurry of clay particles in a liquid would be sufficient. The preferred granular solid differs from support materials of the prior art in that in many known materials, large surface area was obtained by the provision of very fine particles, such as fines, silt, dust and sand. By way of comparison, the inventors have found that a preferred particle size is granular, as described below, which allows for higher flow rates or a lower back pressure of liquid passing through a column, layer, or bed of the composition. This makes the present composition more suitable for commercial applications and continuous flow applications. Moreover, it is believed that handling of finely divided solids can have harmful effects upon humans, so that the present granular materials would also be safer than the very fine materials.
The aluminosilicate substrate and the organoclay composition of the present invention are granular materials, rather than fine materials. A majority of the particles of the substrate and the organoclay, by weight, are within the range of from about 0.25 mm to about 10 mm in diameter, and preferably from about 1 mm to about 3 mm. The particle size of the aluminosilicate substrate can be characterized by retention on a standard mesh screen. When it is said that an aluminosilicate substrate is xe2x80x9cgranularxe2x80x9d, it is meant that the material is composed of particles having a size range where 20%-100% by weight are retained on a #60 mesh screen and not over 20% by weight of the particles are over 4 mm. A preferred clay is characterized by 80%-100% by weight retention on a #60 mesh screen, more preferred is a clay characterized by 95%-100% by weight retention on a #60 mesh screen. Another preferred aluminosilicate substrate is one having particles characterized by retention of at least 50% by weight on a #30 mesh screen and not over 20% by weight of the particles are over about 2 mm.
Preferred aluminosilicate substrates are attapulgite, sepiolite, and zeolite. In particular, it is preferred that the aluminosilicate substrate contain at least 80% by weight of one of these materials. It is anticipated that substitution of another non-swelling, porous, aluminosilicate material having high surface area could be substituted for the preferred aluminosilicate substrates without departing from the scope of the invention. When the an aluminosilicate substrate is defined herein as a certain class of mineral, it is understood for the purposes of this invention that the clay is predominantly composed of that mineral, but it would be expected that other minerals might also be present in minor amounts.
In a preferred embodiment, the clays of the invention are non-swelling clays, such that the volume of the clay particles does not increase significantly upon contact with liquids. The non-swelling clays typically have better physical integrity in an aqueous environment that swelling clays, such as bentonite (montmorillionite). Non-swelling clays have a higher particle hardness and better crush strength in the presence of water, resulting in better maintenance of the desired granular form of the particles.
The alkylamine base of the invention is characterized as a material that is selected from the group consisting of primary, secondary, and tertiary alkylamines. In a preferred embodiment, the alkylamine base has the chemical structure R1R2R3N where at least one of the R groups is an alkyl group containing 6-30 carbon atoms and the other R groups can represent hydrogen atoms. It is more preferred that the alkyl group have from about 10 to 30 carbons and even more preferred that is has about 12 to 30 carbons. Alternatively, a preferred alkyl group is one that has at least about 12 carbons, or more. The preferred alkylamine base is characterized as being nonionic. It is also preferred that the alkyamine base is nonamphoteric. It is believed that incorporation of ionic functional groups onto the subject alkylamines would decrease the hydrophobicity of the resulting organoclay composition, thereby reducing a desirable property of the composition.
A preferred alkylamine base is a fatty alkylamine and more preferably the alkylamine base is a primary fatty alkylamine. A preferred alkylamine base is insoluble in water, and has not been chemically modified prior to contacting it with the aluminosilicate substrate.
Alkylamine bases that are useful in the present invention are oleyl amine, tallow amine, hydrogenated tallow amine, octylamine, dodecylamine, hexadecylamine, octadecylamine, N-tallowalkyl-1,3-diaminopropane, cocoalkylamine, dihydrogenated tallowalkylamine, trihexadecylamine, octadecyldimethylamine, dihydrogenated tallowalkylmethylamine, dioctadecylamine, and the like.
If desired, the alkylamine can be dissolved or dispersed in a solvent to provide adequate coverage of the clay mineral. For the purposes of this invention, the solvent is considered to be any liquid in which the alkylamine base can be dissolved or dispersed. In one embodiment, the alkylamine is dispersed in the solvent in the form of a heterogeneous emulsion or dispersion. In a preferred embodiment, the alkylamine is dissolved in a solvent to form a true homogeneous solution.
The solvent is typically selected from the group consisting of water, alcohols, halogenated solvents, glycols, ethers and combinations thereof. Useful solvents are isopropanol, water, dichloromethane, ethylene chloride and n-propylbromide.
When a solvent is used in the novel method, the solvent is used as a carrier to aid in contacting the alkylamine base with the clay mineral. After the contacting step, the solvent can be removed. It is preferred that the solvent is removed by evaporation or distillation. To facilitate removal of the solvent, a low-boiling solvent is preferred, with a boiling point of 120xc2x0 C. or lower at 760 mm Hg pressure. In another embodiment, the solvent is removed at a reduced pressure relative to the ambient atmospheric condition.
In one embodiment, the solvent is removed until a residual content of less than 10% by weight of the organoclay remains. Preferably, the residual solvent content of the organoclay is less than 3%, and most preferably the residual solvent content is less than 1%.
Solubilizing agents can be added with the solvents to assist the function of dispersing or dissolving the alkylamine modifier. The solubilizing agents can be selected from surfactants, coupling agents, and cosolvents.
Methods of preparation of the subject composition include providing a vessel to contact the aluminosilicate substrate with the alkylamine base. Such vessels can include stirred vessels, rotating vessels, static vessels, ovens, kilns, dryers, and cartridges. The alkylamine base can be applied as a neat liquid or preferably as a solution, with the use of spray nozzles or bars or other suitable means to deliver a liquid into contact with a solid. Preferably, a means is provided to heat the treated clay to assist in removing the solvent and residual moisture. In one embodiment, the organoclay composition is dried at a temperature between 20 and 250 degrees Celcius. Preferably, the organoclay is dried at a temperature between 40 and 150 degrees Celcius, and most preferably the organoclay is dried at a temperature between 50 and 100 degrees Celcius.
In the case where nonaqueous solvents are used in making the organoclay composition, recycling of the solvent is preferred for economic and environmental reasons. In the embodiment where water is used as the solvent, the drying temperature is preferably between 100 and about 250 degrees Celcius.
It is preferred that the weight ratio of the alkylamine base to aluminosilicate substrate is between 0.01:1 and 2:1, more preferred is a ratio of alkylamine to aluminosilicate is between 0.05:1 and 1:1, and even more preferred is a ratio of alkylamine to aluminosilicate is between 0.1:1 and 0.6:1.
The subject organoclay compositions have been found to be useful in the purification of contaminated liquids. Methods of purification of liquids with a subject organoclay composition include absorption, adsorption, chelation, complexation, and association. In general, the contaminants migrate into the organoclay and the organoclay is then separated from the remaining liquid. This can be accomplished in a flow-through continuous or batchwise process, using a cartridge or other vessel containing the organoclay composition and allowing contact with the contaminated liquid.
For cartridge applications, a granular composition is preferred. The particle size of the organoclay composition can be characterized by retention on a standard mesh screen. Useful aluminosilicate substrates include those that would be 20%-100% by weight retained on a #60 mesh screen. Preferably, the organoclay composition is characterized by 80%-100% retention on a #60 mesh screen, and more preferably, the organoclay composition is characterized by 95%-100% retention on a #60 mesh screen. Another preferred size range of the subject granular composition is that at least about 50% by weight of the material is retained on a #30 mesh screen.
In another embodiment, the absorbent composition is added to the contaminated liquid and the contaminant is substantially absorbed, allowing for removal of the organoclay composition as a solid or slurry. In a further embodiment, a finely divided organoclay is added to the contaminated liquid and separated optionally with assistance from coagulants or flocculants. Alternatively, the organoclay is added and mixed with the contaminated liquid until the mixture solidifies for removal or disposal. In each method, the organoclay provides a means to separate the contaminants from the bulk of the remaining liquid.
The utility of the subject organoclay compositions in purifying contaminated liquids is surprising in that the organoclays are typically hydrophobic in nature. In spite of the hydrophobicity, the organoclays have been found to be effective in treating aqueous systems, including water contaminated with hydrocarbons or metals. The organoclays of the prior art were substantially based on the use of cationic quaternary amine modified clays, which would result in a more hydrophilic composition than those of the current invention.
The contaminated liquids to be treated by the subject compositions include aqueous and nonaqueous systems, salt water, produced water, and systems containing toxic, hazardous, or undesirable materials. Specifically, the liquids can contain contaminants selected from the group consisting of oil, grease, hydrocarbons, pesticides, heavy metals, radioactive waste, colored materials, odor-causing materials, suspended solids, turbidity, haze, paint, solvents, resins, condensate, bilge water, industrial effluent, deinking waste, surfactants, emulsified materials, microorganisms, MTBE, BTEX, BOD, COD, and combinations thereof.
It is believed that the subject organoclay compositions are capable of immobilizing the impurities in the hydrophobic pores, making the resulting mixture of organoclay and contaminants less hazardous than the contaminated liquid. This immobilization of wastes is significant to the classification of the resulting mixture, such that the contaminants might not be leachable and the material could pass a TCLP test. A further benefit of using the subject organoclays to purify contaminated liquids includes minimizing the volume of a waste.
The following examples describe preferred embodiments of the invention. Other embodiments within the scope of the claims herein will be apparent to one skilled in the art from consideration of the specification or practice of the invention as disclosed herein. It is intended that the specification, together with the examples, be considered to be exemplary only, with the scope and spirit of the invention being indicated by the claims which follow the examples.
In the examples all percentages are given on a weight basis unless otherwise indicated.
The alkylamine bases were provided in liquid or solid/wax form, and are available from Sigma-Aldrich, Milwaukee, Wis. or from Akzo Nobel.
Attapulgite was provided in the form of a granular solid, and is available from MinTech International, Bloomington, Ind.
Zeolite was provided in the form of granular clinoptiloloite, and is available from US Zeolite Co., Arvada, Colo.
The organic solvents used were of technical grade, used without purification, and are available from Sigma-Aldrich, Milwaukee, Wis. The water was distilled prior to use.
Examples 1-14 show the production of organoclay compositions of the present invention. Examples 15-16 show the production of comparative organoclay compositions of the prior art. Example 17 represents unmodified attapulgite clay for comparison.
A. In a suitable container a 1-50% solution by weight of amine in water was blended and heated to 50-90xc2x0 C., or above the melting point of the amine, with agitation. A nonionic or cationic surfactant can be added to facilitate emulsification of the amine in water. Once the amine was fully melted and blended, it was quickly added with good agitation to the clay, such that a ratio of amine:clay was 0.05:1-1:1. The slurry of water, amine and clay was placed in an oven at 105-110xc2x0 C. for 24-48 hours with periodic mixing.
B. In a suitable container a 1-50% solution by weight of amine in a solvent such as isopropanol was blended and heated to 30-70xc2x0 C., or until the amine is dissolved, with agitation. Once the amine was fully melted and blended, it was quickly added with good agitation to the clay, such that a ratio of amine:clay was 0.05:1-1:1. The slurry of solvent, amine and clay was evaporated then placed in an explosion-proof oven at 105-110xc2x0 C. for 24-48 hours with periodic mixing.
C. The clay modification procedure was also conducted in a heated rotating drum, equipped to rotate axially at a 45xc2x0 offset from vertical. The amine and water were placed in a rotating drum and heated to 40-90xc2x0 C. or until the amine was fully melted and blended. A nonionic or cationic surfactant can be added to facilitate emulsification of the amine in water. The clay was then added to the heated amine/water blend. The temperature was increased to 105-110xc2x0 C., the water was allowed to evaporate, and the clay was allowed to dry.
D. The solvent based clay modification procedure was also conducted in a heated rotating drum. The amine and solvent, typically isopropanol, were placed in a rotating drum and heated to 30-70xc2x0 C. or until the amine was fully melted and blended. The clay was then added to the heated amine/solvent blend. The temperature was increased to evaporate the solvent, then the clay was allowed to dry at 70-110xc2x0 C.